Engine starter



INVENTOR d Qa/4M ATTORNEW Patented Aug. 1, 1944 ENGINE STARTER Herbal A. Thornburg, And General Motors Corpo corporation of Delaware erson, Ind., assirnor to ra tion, Detroit, Mich., a

Application January 6, 1942, Serial No. 426,161

('Cl. 'i4-6) 3 Claims.

This invention relates to apparatus for starting internal combustion engines and has among its objects the provision of improved starter unit comprising an electric motor, a switch for connecting the motor with a current source, a rotatable member driven by the electric motor and moving axially into engagement with a rotatable member of the engine to be started, torque multiplying and speed reducing gearing between the 'u shaft of the electric motor and said shiftable member and an electromagnet for moving said shiftable member and for closing the starting motor switch.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred embodiment of the present invention is clearly shown.

The figure of the drawing is a longitudinal sectional view of an engine starter unit embodylng the present invention.

In the drawing, the starting motor 26 comprises a fleld'frame 2| attached by screws 22 to an end frame 26 and by screws 24 to an end frame 25 to-which a gear housing 26 is attached by screws 21, The end frames 23 and 25 support ball bearings 26 and 29 respectively for rotatably supporting the motor armature shaft 36 carrying an armature 3| and a commutator 32 engaged by brushes not shown. The amature 3| rotates in a field provided by a plurality of pole pieces 66 surrounded by field windings 34 which are in series with the windings of the armature.

The member which connects the starting motor with a rotatable part of the engine to be started is the axially shiftable driving member 46 providing a jaw clutch element 4| for engagement with a similar Jaw clutch element provided by a shaft of the engine to be started. Member 46 includes a tubular hub 42 splinedly connected at 46 with a tubular shaft 44 provided with flanges 45 and 46 which support inner bearing races 41 and 48 of ball bearings 46 and 56 respectively, the outer races 5| and 52 of which are supported by the housing 26. Races 41 and 46 are tightened against balls 46 and 56, respectively by turning a nut 45a threadedly engaging flange 45 of shaft 44. Thus the connecting member 46 and its supporting and driving shaft 44 are rotatably supported by the frame 26.

, Screws 55 secured to the flange 46 of shaft 44,

blocks 51 and washers 56 which support the inner races 56 of ball bearings 66 whose outer races 6| support planet gears 62 meshing with a stationary ring gear 66 secured by screw 64 to housing 26. The planet gears 62 also mesh with a sungear 66 provided by the hub 61 of a disc 66 having a flange 66 providing an internal gear 16. The hub 61 is provided with a bearing sleeve 1| journalled on the extension 12 of the shaft 44. Internal gear 16 meshes with a gear 15 attached by a key 16 to the armature shaft 66. A nut 11 which is screwed onto the left end of the shaft 44 retains the hub 61 of the disc 66 upon the shaft extension 12. Thus the motor armature shaft 66 is drivingly connected with the axially shiftable driving member 46,

'Ihe means for shifting the member 46 includes a rod 66 which extends through the shaft 44 and the member 46. Intermediate itsends the rod 66 is attached to a disc 6| which is provided with longitudinal grooves 62 engaging the splines 46 of the shaft 44. Therefore the disc 6| and the rod 86 are connected withl the shaft 44 so as to rotate therewith. A spring 63 is located between the hub 64 oi' disc 6| and an internal shoulder 65 of the member 46 thereby urging the member 46 toward the right until it engages a nut 66 screwed upon the right end of the rod 66. The rod 66 is urged toward the left by a spring 61 located between an internal shoulder 66 of the shaft 44 and a thimble 66 mounted on the left end of rod 66 and secured by a pin 66. .Thus the spring 61 operates to move the rod 66 toward the left until the disc 6| engages the internal shoulder 44a of shaft 44. The normal location of the member 46 is determined by the adjustment ofthe nut 66 on the right end of the shaft 66. When the rod 86 is moved toward the right, the jaw clutch 4| will be caused to engage a companion jaw clutch on the shaft of the engine to be started. Then the motor 26 is caused to operate to turnthe member 46 in order to crank the engine. When the engine becomes self-operative the jaw clutch on the engine part will run ahead of the jaw clutch 4| thereby causing clutch 4| to move intermittently toward the left against the action of spring 6l until the shaft 66 is returned to its normal position.

The starter unit includes an electromagnet |66 for actuating a switch which connects the starting motor with a current source and for causing movement of the rod 66 toward the right. This electromagnet comprises a magnetizable frame which includes a stationary core |6| having its shank riveted to magnetizable discs |62 and |66.

Disc |62 bears against a magnetizable tube |64 within a magnetizable tube or outer shell |65 which overlies both discs |62 and |63 and has a flange |66 formed against the left face of disc |03. The shell |05 overlies the periphery of magnetizable discs |01 and |55. A flange |00 of the shell |05 is formed against the right face of disc |08. Disc |05 is centrally apertured to receive a magnetizable sleeve support having its right end portion extending through a centrally apertured plate and a hole |I2 in the end frame 25. The sleeve ||0 is press-fitted through the plate iii which is secured by screws not shown to the frame 25. The core |0| and the sleeve |i0 together support a nonmagnetizable tube ||5 having a left end flange ||5 and an intermediate flange or bead ||1. Flange III spaces the disc |02 from a magnetizable disc ||5 which is in contact with the tube |04. The bead ||1 spaces the disc |01 from a magnetizable disc i9 which is in contact with the tube |04. The tube H5 supports a magnetizable amature |20 connected by a screw stud |2| and a pin |22 with a link |23 having a slot |24 receiving a pin |25 carried by a lever arm |25 having a hub |21 pinned to a shaft |28 journaled in a bracket |23 integral with end frame 25. Hub |21 is integral with a lever arm |30 carrying a pad |3| for engaging the thimble 83 on the left end of rod 00.

The armature |20 is supported by the tube ||5 for sliding movement, but the armature |20 does not rotate since it is provided with a groove |33 engaged by a tongue |34 integral with the disc |01. The tube i|5 is provided with a notch |35 .to provide clearance for the tongue |34. In order to exclude foreign matter from the interior of the tube H5, the armature carries a felt ring |35 which is retained by a resilient split ring washer |31 which is retained by the flange |33 provided at the right end of armature |20. Ring |35 bears against the interior of tube i i5.

'I'he electromagnet includes an armature attracting coil |40 and an armature holding coil |4|. Initially both coils are excited in order to attract the armature |20 toward the core |0|. Movement of the armature |20 toward the left effects the closing of the motor switch to be described and also the short circuiting of the main attracting coil |40 leaving the coil |4| in circuit to maintain the closure of the starting motor switch and the engagement of the jaw clutch 4| with its companion clutch member.

The motor switch includes a pair of spaced contacts one of which is shown at |44. These contacts are provided by the ends of terminal screws |45 (only one shown) insulatingly supported by a plate |45 attached by screws |41 to a switch housing |48 which encloses not only the switch but the terminals and connections between these terminals and the electric motor. Housing |43 is shaped to conform to the cylindrical surface of the starting motor and is provided with a removable cover |49 secured by screws |50. The contacts |44 are engaged by a contact disc |5| insulatingly supported by nonconducting sleeve |52 which is slidable on a rod |53 which is attached at its right end to the armature |20 and which slides through a central hole in the core i0 I. The left end of the rod |53 carries a nut |55. The sleeve |52 is normally urged against the nut |55 by a spring |55 bearing at its left end against a washer |51 which bears against the sleeve |52. Spring |56 bears at its right end against the C- washer |58 received by a groove |59 in the rod |53. One of the contact screw terminals |45 is connected by a cable with the current source the other contact terminal screw |45 is connected by a strap |50 with certain brushes not shown. Other brushes are connected with one end of the field circuit. The other end of the held circuit is connected by wire |0| with a terminal bolt |52. Therefore when the two contacts |44 are bridged by the contact disc |5|, the electric motor 25 will be connected with a current source and will operate through the gears to turn the shiitable driving member 40 in order to crank the engine.

The electromagnet |00 is controlled by a push button switch (not shown) located near the driver of the vehicle which is equipped with this engine starter. The closing of the switch causes the electromagnet |00 to operate to shift the iaw clutch 4| into engagement with a similar jaw clutch on the engine to be started and also to cause the disc |5| to bridge the switch contacts |44 in order to cause the motor 20 to rotate the Jaw clutch 4|. When the engine becomes self-operative its jaw clutch runs ahead of the jaw clutch 4| which is caused to snap back and forth under the action of the spring 33. When the push button starter control switch is released, the electromagnet is deenergized and spring 51 causes the jaw clutch 4|, the armature |20 and the switch disc |5| to be returned to normal position.

The frame |45 includes an end wall |4Ia which is secured to disc |03 of electromagnet |50. Frame |48 supports a nonconducting tube |40b which cooperates with end wall |40a and disc |45 to enclose the starting motor switch.r

The left end of starting motor armature shaft 30 is provided with a square portion 30a for receiving a removable crank by which the shaft 30 may be turned manually in event of failure of the current source.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

l. An engine starter comprising an electric motor having a field frame, an armature shaft and end frames attached to the field frame and carrying bearings which support the shaft. a gear housing attached to one of the end frames of the motor, a tubular shaft supported by the housing, speed-reduction gearing in the gear housing for connecting the armature shaft with the tubular shaft, a driving member for making engagement with a shaft of the engine to be started. said member being supported by the tubular shaft centrally thereof, means provided by the tubular shaft and member for drivingly connecting said shaft and member while providing for longitudinal movement of the member into and out of connection with the engine shaft. means for effecting longitudinal movement of the member and including a rod extending through the tubular shaft and into the gear housing and including an electromagnet having an armature and mounted upon the motor field frame and a devicf located in the gear housing for transmitting motion from the armature of the electromagnet to said rod, and a motor switch supported by the motor field frame and closed by the armature of the electromagnet as the latter is moved to operate said rod and cause engagement of said driving member with the engine shaft.

2. An engine starter comprising an electric motor, a tubular shaft driven by the motor, a driving member for making engagement with a shaft of the engine to be started, said member being supported by the tubular shaft centrally thereof, means provided by the shaft and member for drivingly connecting the shaft and memasalta ber while providing for longitudinal movement of the member into and out of engagement with the engine shaft, a rod extending through the shaft and'member, a spring within the shaft for maintaining the rod in a normal position relative to the shaft, a second spring within the shaft for transmitting motion yieldingly from the rod to the member in a direction to move the member into driving engagement with the engine shaft, a part carried by the rod and engaging the member to retract it from the engine shaft when the rod returns to normal position under the action of the nrst spring, means for moving the rod away from normal position in a direction toward the engine shaft, the tubular shaft being provided lnternally with longitudinal splines and the driving member being provided externally with longitudinal splines engaging the splines of the shaft, and a part attached to the rod provided externally with longitudinal splines also engaging the splines of the shaft, whereby the rod rotates with the shaft, and rotation of the rod relative to the springs is prevented.

3. An engine starter comprising an electric motor, a tubular shaft driven by the electric motor and provided intermediate the ends of its central bore with an apertured partition providing an internal annular ilange and provided with internal longitudinal splines extending from the annular nange vto the end of the shaft nearest ,o

toashaftoftheenginetobestarted,adriving member for making engagement with the engine shaft and supported by the shaft centrally thereof and having longitudinal splines engaging the splines of the shaft, a rod extending through the shaft and member, a part attached to the rod and having splines engaging the splines of the shaft, a spring located within the shaft and between the annular flange and the end of the shaft remote from the driving member, means operatively connecting the spring with the rod so that the rod is urged away from the engine shaft and the rod-part attached'to the rod normally bears against the annular i'lange on the side thereof nearest to the connecting member, a spring located between said rod-part and the connecting member to transmit motion yieldingly from the rod to the connecting member in a direction to move it into engagement with the engine shaft, a second part attached to the end of the rod adjacent to the connecting member for establishing the normal position of the connecting member relative to the rod and for retracting the member from the engine shaft when the rod returns to normal DOsition under the action of the rst spring, and means for moving the rod away from normal position in a direction toward the engine shaft.

HERBAL A. THORNBURG. 

